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H EIGHBAUM DELAYING THE MOVEMENT 0F PROJEGTILES IN- PNEUMATIC GUNS.

Patented Aug. 5, 1890.

l l ll E Wz wr/ am fii'fawireya" is PEYERS 0a., mmcru-mo I UNITED STATESPATENT OFFICE.

HENRY EIOHBAUM, OF LONDON, ENGLAND.

DELAYING THE MOVEMENT 0F PROJECTILES IN PNEUMATIC GUNS.

SPECIFICATION forming part of Letters Patent No. 433,648, dated August5, 1890. Application filed April 16, 1890. Serial No. 348,206. (Nomodel.) Patented in England October 30, 1889, No. 17,180.

To all whom it may concern.-

Be it known that I, HENRY EICHBAUM, a citizen of the United States, atpresent residing at London, in England, have invented certain new anduseful Improvements in or relating to Means for Delaying the Movement ofthe Projectile inPneumatic Guns, (for which I have obtained patent inGreat Britain, No. 17,180, dated October 30, 1889,) of which thefollowing is a specification.

The object of this invention is to prevent the projectile in a pneumaticgun from being blown out by the first impulse of air that en,- ters thebarrel before the pressure of the air has accumulated in sufficientforce to act efficiently to propel the projectile, and thus to secure agreater range without increasingthe air-pressure toa dangerous degree.As the projectiles of pneumatic guns are generally intended to becharged with high explosives, it is important in thus delaying the startof the projectile to so arrange the means by which it is accomplishedthat there shall be as little shock as possible both in the start of theprojectile from a state of rest and in its release from the force thatresists its movement. The manner in which such delay and gradual startof the projectile is provided for in this invention is shown in thedrawings accompanying this specification, in which Figure 1 represents alongitudinal section of the breech end of a pneumatic gun with thebreech closed and a projectile in external view ready to be discharged.Fig. 2 represents alongitudinal section, on a larger scale, of thoseparts of the barrel and projectile in which the device is located. Fig.3 shows a modification of part of Fig. 2.

The same letters refer to the same parts in all the figures.

A is the gun barrel or tube, A being an opening through which air isadmitted to impel the projectile, and A the breech-block.

B is the projectile, B being the chamber containing the explosive, and Ba gas-check to prevent the impelling air passing by the projectile inthe barrel. Behind the gas-check the shell of the projectile is extendedto allow of a wide dovetailed recess B being formed in itscircumference, and this recess is filled with a ring B of softmetal-such aspewter, type-metal, lead, or any other suitable material-ofsomewhat larger diameter than the rest of the projectile. A uniformdiameter of this ring slightly larger than the bore of the a gun, asshown in Fig. 3, may in some cases be suiticient to delay the projectileto the desired extent without shock either at the start or release; butit is shown in Figs. 1 and 2 of such external shape that while at eachedge of the recess B it is the same diameter as the shell of theprojectile it is swelled in the middle to a larger diameter, from whichit tapers to either edge. To accommodate this increased diameter of theprojectile at this point, the barrel at the breech is formed With achamher A of a diameter sufiiciently large to allow the insertion of theprojectile, as shown in the drawings.

It is evident that as thus made the pro jectile cannot be dischargedfrom the gun without the removal of all that part of the soft-metal ringwhich projects beyond the diameter of the barrel along which it has totravel to reach the muzzle. The ring therefore ofiers a definiteresistance to the movement of the projectile, which will allow theair-pressure to accumulate to any desired amount, dependent chiefly uponthe diameter and shape of the ring, the quality of the metal, and theshape and condition of the edge which strips it. To remove theprojecting metal of this ring so that the projectile may be discharged,I place in a suitable position in the gun-barrel a cutting or strippingring, preferably of steel and of the same i11- ternal diameter as thebore of the gun, or slightly smaller, which acts as a cutter or scraperto strip off the soft metal as the pressure of the air forces theprojectile forward. This ring is shown at A Figs. 1 and 2. It may bemade in sections, so as to be placed from the inside in the recess, inwhich it is shown, or it may be made in one piece and the barrel soconstructed as to allow of its insertion or removal. In either case itis desirable that it should be hardened and tempered and its scraping orcutting edge a kept in uniform condition, as also the rings 13 of theprojectiles, so that the amount of re sistance should be the same withall projectiles.

In the drawings the steel ring is shown as just on the point of cuttingthe soft metal;

but, if desired, a short run maybe allowed the projectilebefore the.steel engages the soft metal.

As shown in the drawings in Figs. 1 and 2,

it is evident that the projectile would move slightly at the firstimpulse of the air, and

, that as it advanced the increase of the amount of soft metal to beremoved would oppose more and more resistance to the movement of theprojectile. This would be met by the accumulation of the air-pressure,which would at last overcome the resistance offered at the greatestdiameter of the soft-metalrin g. To

provideagainst a shock by the sudden cessation of the resistance, thesoft-metal ring is tapered oif at the rear edge, as'already described,and whenv this has passed the steel ring the projectile is free totraverse the guntube.

It will beperceived-that considerable variations may be made inthedetails of this invention without departing from the spirit of it. Forexample, the shape, size, position, or

general arrangement of the ring B and the place or manner of connectingit to the projectile, or a number of rings, interchangeable .orotherwise, in anumber of segments might be used and similarly with thering A for which many equivalents might be devised. The placing of thesoft metal in the gun and i the stripping-edge upon the projectile wouldfor many reasons be so undesirable that it is 'unnecessary to dwell uponthe numerous modifications which could be devised upon those lines. V I

The term soft metal is applied to the ring B in this specification; butit will be understood that other materialssuch, for example, as asuitable cement-might be used in place of metal, and the term soft metalis intended to embrace such other materials.

Merely to compare the purpose of the softmetal sabot of the ordinaryshell with the purpose of the soft-metal ring of the present inthediameter of the projectile is concerned,

entirely removed before it enters the guntube proper. It'is .notintended to enter at all into the riding-grooves (if any) of the gun,and its special purpose is to retard the start of the projectile untilthe predetermined pressure has been attained. j a

Iclaim 1 1. The within-described method of retarding or delaying themovement of the projectile in a pueumaticegun barrel or tube, whichconsists in the removal of a portion of softmetal obstruct-ion upon theprojectile as it moves forward in the gun barrel under pressure of thepropelling-fluid, substantially in the manner described.

2. As a means forretarding or delaying the movement of the projectile ina pneumaticgun barrel or tube, a soft-metal obstruction upon theprojectile and a cutting or stripping movement of a projectile inapneumaticegun barrel v oi-tube, a soft-metal ring surrounding theprojectile and extending bcyond 'the surface thereof and a cutting orstripping ring arranged within the barrel or tube, substan-.

tially as andforthe purpose set forth.

In testimony whereof I have hereunto set my hand inthe presenceof thetwo subscribing witnesses. t

Witnesses:

HARRY B. BRIDGE,

HAROLD WADE.

edge upon the gun, substantially as described. I 3. As a means forretarding or delayingthe- HENRY EICHBAUM.

